Planetary transmission



Feb 15, 1943` H. E. cARNAGuA 2,311,209 v PLANETARY TRANSMISSION I Filed Aug. 25, 1941 x ,do 19 @ZM @W Patented Feb. 16, 1943 oFElcE PHSSUED Harold E. Gamma, Muncie, Ind., Vassignm- Borg-Warner Corporation,

poration of Illinois Chicago, lll., a oor- Application August 25, 1921, Seriali No. 408,171

s claims. (c1. 'i4-zen) This invention relates to power transmitting devices of the planetary gear type and particularly to such a transmission which is adapted to provide a plurality of forward driving speed ratios including an overdrive ratio.

'Ihe present day internal combustion4 engines of the type and proportion generally used in an automobile require the use oi' a variable speed transmission between the engine and wheels in order to satisfy generally accepted performance requirements. Such a transmission, however, if satisfactory as to speed ratios is apt to be bulky and dimcult to manipulate. To reduce the size of such a transmission it hasl been proposed to take advantage of certain inherent characteristics of the phnetary type of gearing whereby but one planetary gear set will besuicient to provide a reverse ratio, a neutral, a direct drive and an overdrive. The simplicity of gearing thereby obtained is 'somewhat detracted from, however, by the resulting complexity of the controls necessary to bring about the ratio changes.

The principal object of this invention is to provide a multiple ratio single planetary transmission wherein the controls are improved and simplified so as to render the transmission less expensive to build and maintain.

Another object of this invention is to provide a' transmission wherein a manually operated direct drive is secured and an automatic shift is made between direct and an overdrive ratio, the shift employing hydraulically controlled means.

These and other objects and features of the invention will become apparent from the following description when taken together with the accompanying drawing in which:

Fig. lis a side elevation in section of the improved transmission; and

Fig. 2 is a fragmentary elevation taken along lines 2-2 of Fig. 1, showing in detail the form of one of the coupling means.

Referring now to the drawing .for a detailed description of the invention, I is a drive shaft which is adapted to be connected to a prime mover such as the internal combustion engine of an automobile or to the output of an 'auxiliary I3 meshing with a ring gear Il formed on the interior of a. drum I5, and with a sun gear I6 formed on the exterior of a sleeve I1. Said planet gears are mounted on a carrier IB with which is rotatable a large drum I9 and a smaller drum 20, drum I9 extending to the right of carrier Il as viewed in Fig. 1 anddrum 2U extending to the left. Drum I9 is i'ixed axially with respect to carrier III by means of a shoulder 2l on one side and a ring 22 on the other side. Similarlypdrum 2l is fixed axially with respect to carrier Il by means of and a snap ring- 24 on I8. Both drums il and rotate with carrier Il. The right hand end I5 is provided with splines 25 drivingly connected a belled portion 28 of driven shaft Il and an internally toothed clutch element 21. Itl is apparent that ring gear Il and clutch element 21 are constrained to rotate with driven shaft II at all times.

The right hand end (Fig. provided with clutch teeth 2l the other side of carrier y2li are attached to and (rig. 1) of ring gear 4drum i) of drum le is which are of the same size as internal clutch teeth 29 on clutch velement 21. A washer 3.0

teeth and prevents excessive axial movement'between ring gear I4 and planetary gears I3.

Smaller drum 20 is provided with external splines Il which mesh with a slidable sleeve 32 which is likewise provided with external teeth or splines 3l. Said sleeve 32 is adapted to slide axially along splines SI to assume a plurality of positions. teeth- 33 engage with teeth 24 on a plate 35 which is bolted or otherwiseV non-rotatably secured to the casing 38 of the transmission. When so engaged, sleeve 32, its associated drum member 20 and carrier I8 are all held against rotation, thereby making possible a reverse drive through planetary gear set I2,

Loosely mounted on drive shaft I0 and within belled portion 26 of driven'shaft II is a hub member 31 having external teeth 38 formed on one end thereof and a series of cams 39 formed on the other end. Between cams 39 and the intransmission. The driven shaft is shown at Il and is adapted to be connected to a load such as the rear wheels of an automobile (not shown). Between drive shaft I0 and driven shaft II is a planetary gear set I2 which is adapted to be connected to the shafts by means hereinafter to be .described to produce a reverse drive, a neutral,

a direct drive and an overdrive. Said planetary gear set is comprised of 6ne or more planet gears ner surface of belled portion 26 are located rollers-40 which constitute a one-way or free-wheeling drive between hub member. 31- and driven shaft il.

Immediately adjacent hub member 31 is a collar 4i which is splined to drive shaft I0 so as to be rotatable therewith. Said collar 4I has external splines or teeth I2 on which is mounted an internally splined sleeve 43, said sleeve 43 bea shoulder 23 on one side with which are.

spaces the twoclutch In the extreme left hand position,

ing axially slidable relative to collar 4I. Said sleeve 43 is connected to sleeve 32 by means of a plurality of pins 44 passing through carrier I8 and slidable axially relative thereto. Thus sleeve 32 and sleeve 43 are constrained to move together. The' connection between pins 44 and sleeve 43 is such as to permit relative rotation therebetween so that if sleeve 32 is in its extreme left hand position wherein it is held against rotation, sleeve 43 may be rotated by the drive shaft.

Sun gear sleeve I1 is provided at one end with a toothed clutch element 45 which is adapted to be engaged by the internal teeth of sleeve 43 when the latter is moved to its extreme left hand position. It will be apparent now that in this position sun gear I6 will be driven by the drive shaft through sleeve 43, and carrier I8 will be held against rotation, thereby causing ring gear I4 to be driven reversely `and with it the driven shaft II. Sleeve 43 is also provided with external teeth 46 which are adapted to engage teeth 28 and 29 on drum I9 and clutch element 21, respectively. When engaged with either of these teeth, the internal splines likewise engage teeth 38`0n hub member 31 and thereby transmit drive simultaneously to this member.

When teeth 46 engage teeth 28, drum I9 and hub member 31 are both driven by the drive shaft and, depending upon whether or not sun gear I6 is held against rotation, the transmission will be either in direct drive or in overdrive, direct drive being secured through the free-wheel connection established between cams 39, roller 40 and belled portion 26 0f driven shaft II.

When sleeve 43 is in its extreme right hand position so 4that teeth 46 engage teeth 29 and do not engage teeth 28, said sleeve 43 provides a direct connection between belled portion 26 and drive shaft I so as to lock out the free wheeling action of rollers 40. In this position direct drive only will be obtainable.

The position of sleeve 32 and sleeve 43 is determined by means of a manually controlled disc 41 which is secured to..slee ve 32.

The transmission illustrated is designed to produce an overdrive automatically through the planetary gear set. The latter is conditioned for overdrive operation by arresting sun gear I6 and coupling teeth 46 on sleeve 43 with teeth 28 on drum I9. The means by which sun gear I6 is held against rotation will now be described.

It will be observed that on the left hand end (Fig. 1) of sleeve I1 are formed external teeth or splines 48. An internally toothed disc 49 meshes with splines 48 to cause said disc to rotate with sleeve I1 and sun gear I6. Around the outer periphery of disc 49 are teeth 50 as shown in Fig. 2, the teeth having sloping or cammed outer surfaces I. Located within housing 36 is a bore 52 within which is reciprocable a piston 53. The outer end of piston 53 is formed into a tooth 54 resembling a pawl the outer surface 55 of which is also slopedor cammed. The inside of piston 53 is formed into a rod 56 which passes through a second piston 51 located in a larger bore 53. The end 59 of rod 56 is threaded to receive a nut60 which forms an abutment for piston 51. A coil spring 6I reacts against the shoulder 62 formed by the junction of bores 52 and 58 and urges piston 51 outward in a direction to withdraw rod 56 and its associated piston 53 and pawl 54 from'contact with teeth 50 on disc 49. A second coil spring 63 is designed specifically to take up the lost motion connection between pistons 53 and 51 by tending to separate the pistons.

Thus when fluid under pressure is admitted behind piston 51 the pressure will be transmitted through spring 63 to piston 53 which in turn will be urged toward disc 49 to engage pawl 54 with teeth 50. If at the moment there is relative rotation between teeth and pawl 54, engagement will be precluded by the camming action of the surfaces 5I and 55 against one another. 'I'he pressure of the fluid will be absorbed in spring 63 so that piston 51 may assume its fully engaged position and remain in such position independently of the movement of piston 53. At the instant when relative rotation between the disc and pawl ceases and slightly reverses its direction, pawl 54 will engage teeth 50 and thus arrest the rotation of sun gear I6.

The automatic control for the fluid pressure will now be described. The fluid circuit includes a conduit 64 leading to a sump or other reservoir of fluid such as oil, which conducts the fluid to a suitable power driven pump 65 and thence to a conduit 66 formed in a rotatable valve block 61 which is trunnioned in casing 36 at 68 and 69. The pressure within conduit 66 is regulated by means of a suitable pressure relief valve 1l. Valve block 61 is connected by means of gears 1I and 12 to driven shaft II so as to be rotatable in response to the rotation of said driven shaft. Within valve block 61 is a radial bore 13 in which is mounted a valve 14. Said valve has a circumferential groove 15 in communication with a central vent groove 16, and a relatively wide circumferential groove 11 located adjacent groove 15. A spring 18 acting against a washer 19 and a bolt 80 threaded to valve 14 biases said valve radially inward. It will be noted that the bulk of the valve is eccentric to the axis of rotation and that this eccentricity will tend to increase as the valve is rotated. The spring thus counteracts the centrifugal force developed in the rotating valve and it may be adjusted to provide any suitable initial tension. A conduit 8| in valve block 61 is so located with respect to conduit 66 and circumferential groove 16 and 11 that when the valve is in the position shown, that is, the position assumed when it is not rotating, conduit 8| will be vented through groove 15 and conduit 16, and at the same time conduit 66 will be blocked off. When the valve is rotated at some predetermined speed, say for example a vehicle speed of 23 miles per hour, it will assume a position such that circumferential groove 11 will connect conduit 66 with conduit 8| and admit fluid pressure past the valve.

Conduit 8I connects with conduits 82 and 83 in casing 36 which ultimately connects with bore 58.

It will be evident from the foregoing description that when control disc 41 is in its first left hand position (Fig. l) the planetary gear set and 'clutches'will be set for reverse operation. When control disc 41 is in the position shown in full lines the transmission is in neutral and no power can be transmitted between the shafts. In the next position the planetary gear set will be in condition for free-wheeling directl and overdrive, and in the farthermost right hand position, the transmission will be set for lockedup direct drive. When control disc 41 is set for direct drive and overdrive operations, valve block 61 is rotated and with it is rotated valve 14. Up to the predetermined speed for which the valve is set, conduit 8| will be vented through the @villas new@ behind in" te A,ed a,

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claims-.1er

"Il C18-imite l-. netransmiss :shattsseplanetarvngeam ctheozshaitsitexiestaiblish A zrl'rive'iratios Qf gmane cle in the narrower: port connectie ,themen between the steps urging the said one of the pistons in a direction to take up the lost motion connection, and resilient means for transmitting .the pressure from one piston to the other; and conduits connecting the source of iluid underpressure, the valve and the hydraulic means, said valve being adjusted to admit fluid under pressure to the hydraulic means at a predetermined speed of the driven shaft to establish overdrive. y

2. A transmission comprising drive and driven shafts, planetary gearing connectible between the shafts' to establish reverse, direct and overdrive raltios, a source of uid under pressure, a

centrifugally operable valve driven from the driven shafts, a positive brake for arresting the rotation of thesun gear to establish overdrive, hydraulic means for operating the brake, said hydraulic means comprising a fixed housing having a bore therein, a step in the bore, a piston in the wider portion of the bore, a second piston in the narrower portion of the bore, a\lost motion connection between the pistons, resilient means -between the steps and one of the pistons for urging the said one of the pistons in a direction to take up the lost motion connection, and resilient means for transmitting the pressure from one piston to the other; the brake com- Aone of the/pistons for4 rinsing dinve shaft to esta s a in a third position connecting the shafts to esh #litri i.

get for a two-way drive.

5. A transmission comprising drive and driven shafts, planetary gearing connectibie between the shafts to establish a yplurality of speed ratios, said planetary gea-ring including a, .planet gear carrier, a splined drum rotatable with the carrler, a positive brake for the carrier comprising a xed element and an axially slidable element adapted to engage the xed element, said axially slidable element being mounted to rotate with the drum, an element loosely mounted on the drive shaft, a slidable sleeve mounted for rotation with the drive shaft, an overrunning clutch between the loosely mounted element and drivenshaft, and cooperable clutch means on the sleeve, loosely mounted element and driven shaft, said sleeve in a rst position being disconnected from the loosely mounted element and driven shaft to establish neutral, in a second .position connecting the loosely mounted element with the driven shaft to establish a free-wheel direct drive, and in a third position connecting the shafts together for a'positive two-way drive, and means conecting the slidable sleeve on the drive shaft with the slidable brake element on the carrier drum to cause the two to move in unison, said connecting means preventing the Aengagement of the brake elements when the slidable sleeve is in neutral, free-wheel direct, or positive direct positions.

6. A transmission as described in claim 5, said carrier having a second drum rotatable therewith and extending in the direction of the driven shaft, said drum having clutch means cooperable with the clutch means on the slidable sleeve rotatalble with the drive shaft and eil'ective to couple the drive shaft with the carrier to condition the transmission for overdrive.

7. A transmission comprising drive and driven shafts, planetary gearing connectible between the shafts to establish a plurality ofl speed ratios, said gearing comprising a ring gear, a sun gear and a -planet gear carrier, a sleeve surrounding the drive shaft and rotatable with the sun gear, a brake element on one end of the sun gear sleeve, a clutch element on the other end of the sleeve, a drum on the carrier, means spacing the drum from the brake element, means preventing axial movement between the carrier and drum, a second drum on the carrier and extending in the opposite direction from that of the firstv drum,

means on the second drum preventing relative movement between the drum and carrier in the direction of the brake element, a clutch element on the driven shaft, inproximity to the clutch element on the second drum, spacing means be-l tween the two elements, said spacing means limiting the movement of the second drum and a'ssociated carrier and first drum in the direction of the driven shaft, a collar splined to the drive shaft, a slidable sleeve on the collar rotatable with the collar and having a clutch element lcooperable with the clutch element on the second drum and with the element on the driven shaft, means -for connecting the slidable sleeve with the clutch element onthe sun gear sleeve so as to drive the latter from the drive shaft, a second brake element, and a slidable sleeve on the ilrst carrier drum engageable with the second brake element to arrest the rotation of the carrier, and means connecting the slidable sleeve and the drive shaft collar with the brake elements on the first carrier Adrum so as to cause the two to move in unison. said connecting means in one position connecting the sun gear to the drive shaft and the carrier to the brake element, in a second position disconnecting the drive shaft from the sun gear and the brake element from the carrier to provide a,.n'eutral, in a third position connecting the clutch on the second drum to the drive shaft to provide a -free-wheeling direct drive, andin a fourth position connecting the drive and driven shaftdirectly together.

8. A transmission comprising-'drive and driven shafts, planetary gearing connectible between the shafts and comprising a ring gear, a sun gear and planet pinions meshing with. thek ring and sun gears, a carrier for the planet gears, a brake means cooperable with the carrier to arrest the I rotation thereof, a freely rotatable collar on the drive shaft, an overrunning clutch `between the collar and driven shaft, axially fixed clutch means on the collar, the sun gear, the carrier and on the drive shaft, axially slidable clutch means adapted in one position to connect the drive shaft to the sun gear, in another -position to the carrier and collar, and in a thirdrposition to the. driven shaft and collar,y a slotted brake member on the sun gear, a radially movable pawl adapted to engage the slotted brake member to arrest the rotation of the sun gear, piston means for effecting, radial movementof the pawl to engaged and disengaged positions, a hydraulic circuit including a source of iluid under pressure and conduits for conducting the fluid under pressure to the piston, a centrifugally operable valve in the hydraulic circuit adapted in one position to vent the fluid behind the piston and in another position to admit fluid under pressure therebehind, a gear drive between the driven shaft and valve forl driving thev valve in response to rotation of the driven shaft, and a brake for the carrier, said brake being movable in -unison with the axially slidable clutch element on the drive shaft such that when the sun gear is driven by the drivel shaft the carrier is held against rotation to establish -reverse drive, said valve being adjusted to bias the pawl to yengaged position to establish overdrive when a predetermined speed of rotation is reached. e HAROLD E. CARNAGUA. i 

